Many bowl makers use sanding discs in an electric drill to sand bowls. The idea is to start with a coarse grit disc, then use a succession of finer grit discs to remove scratches left by each previous one. Each disc leaves its own scratches, getting finer and finer as you work through the sequence. But it can be hard to tell whether a scratch was made by the current disc or the previous one. If you sand with 120 grit, then go on to 180, which disc are the scratches from? If you go from 120 to 100 or 150 grit, those discs will be more effective than the 180 at getting rid of sanding scratches. But the smaller the interval, the harder it will be to tell them apart.
Sometimes you can overlook the deepest scratches until the last stage, or even until after you have applied the finish. If you miss the deep ones from the coarser disc they can show badly later.
There is a simple method to distinguish between them. A particle of grit on the upper part of the disc will be moving from left to right as the disc spins clockwise. If the part of the bowl being sanded is moving upwards in the lathe, the scratch that particle makes will run diagonally from top left to bottom right. The angle will depend on the relative rotation speeds – running the lathe slowly will make the angle easier to see. If you reverse the rotation for the following disc, its scratches will run from top right to bottom left. When you can’t see any scratches running the other way, that disc has done its work. Reverse the rotation again and go on to the next one.
You can reverse either the lathe or the drill to give this result. You can also switch between the upper and lower quadrants of the sanding disc. Either way, you will be able to spot deep sanding scratches more easily.
Another benefit is that reversing the direction helps remove projecting fibres. This applies also to hand-held sandpaper, which leaves vertical scratches. This method of getting rid of sanding scratches is not applicable to hand sanding.
Tungsten carbide is a very hard but brittle material used for cutting tips in metalworking. It is now used in woodturning too. I first made some tungsten carbide woodturning tools many years ago. They had a use, but I had to use them fairly forcefully to make them cut. I could not make them sharp enough to cut wood at the lathe, even though carbide has long been used for saw teeth. Recently there has been a lot of publicity given to tungsten carbide woodturning tools. They normally have replaceable carbide tips. They are supposedly formulated to be sharper. However, they are apparently less robust than other grades.
Several companies are now selling tipped tools, and users report very favourably. The tools are expensive, and without information about the carbide grade, you have to take the quality on trust. I would like to make some tipped tools with this woodturning grade carbide. I’ve bought some tips from various sources but the ones I have tried so far don’t keep their edge very long when cutting MDF. MDF is very abrasive and hard on sharp edges. A long-lasting edge is the main reason for using carbide. After a bit of use, the carbide edge feels rough to the touch, and like a sawblade when tried with a fingernail,
Yesterday, I bought a micrograin carbide tip from Robert Sorby. I fitted it to one of my homemade tools to try. First impressions are not good. It didn’t do well on MDF, which I turn a lot. Very likely it would work well on ordinary wood though. And at least the tip has a very generous thickness to allow sharpening with a diamond hone.
Work on the redwood globe stands continues today. I finished the lower leg sections and moved on to the upper, which are tapered. They are made in the same way except that each end has to be callipered to size separately. Here is a block mounted in the lathe.
Note the wooden toolrest. I shall upload an article on making the tool rest soon. A long tool rest is very useful for jobs like this.
This redwood is quite tough to turn. The ripple grain tends to break out quite easily, so it is important to sharpen the gouge and finish with fine cuts.
I’ve been making some more globe stands. I finished some that I turned earlier, and made up a variation on an existing stand, three wanted. To make the job easier I use a couple of finishing aids.
I make holders to help with finishing the stands. Most of the stands that I make have a spindle fitted to a disc at the bottom. I paint them before applying shellac. Before they dry, they are difficult to handle. I made some little blocks with a hole to fit the spindle tenon. They are handles to hold the spindles by. I put the spindle and block in the lathe together to apply the shellac evenly with the lathe running at low speed. The holes in the blocks go right through, so I can use the original centres on the spindles. When the finish is on, I can hold the blocks while the spindles are wet, and the blocks stand the spindles safely while they dry.
The second of my finishing aids are holders for the discs. The holders are square blocks with a small central peg. The peg fits in the screw chuck hole in the underside of the disc. I put the disc and block together on the lathe by pinning them against a small faceplate with the tailstock. I apply the shellac with a brush while the disc is slowly spinning. Without the holder, the disc would have to stay in the lathe until it was dry enough to handle. This is not practicable when doing batches.
Workshop storage is important. A tidy shop makes us much more productive. There is nothing worse than spending hours hunting for some item that you know you have in the workshop somewhere. And if tools don’t have a proper home, they get left on the work surfaces where they are in the way.
Drawer units are best
In my experience, drawers are the best workshop storage option for small items. They don’t trap dust and shavings, they hold more than cupboards, and stuff is easier to see and get out than it is in cupboards. I currently have 84 assorted drawers in my workshop, mostly homemade, but it’s not enough. Today I started on another 4-drawer unit that will fit into a rack of steel shelves that I have. The drawers will hold more than the shelf did and be more useful. I already have a similar unit on the shelf below. They are quick to make, and very rough and ready – I don’t make furniture, just somewhere to keep things.
I make them out of whatever board I have spare, MDF or ply. This unit has sides and a vertical divider of 25 mm MDF and drawers made of 12 mm ply. It’s just a question of sawing the panels to size and cutting rebates and grooves, then assembling with glue and pins.
Make the joints with a router
I made the grooves with the table saw. I used my router table to make the corner joints in the drawers. There is a simple interlocking joint that you can make with one setting of the router. It cuts both parts of the joint without having to change anything.
Dust collection for the router is not good at present. I don’t use it often, but want to improve the enclosure of the table so I can connect it to my dust extraction system. Because it has a sliding insert in the top, I am not sure how to seal it. I want the air flow to pull dust and chips down into the cabinet and away to the extractor. If there are openings in addition to the one where the router cutter is positioned, the suction will not be effective.